Intra-Channel Calibration
There are currently three varieties of intra-channel calibration available:
- Canonical Calibration (2.6GSa/s), i.e no calibration
- The RG calibrations (integral calibration)
- The JW calibrations (differential calibration)
Performance Results
To gauge the perfomance of the intra-channel calibration the period of clock waveforms were measured. This was done using simple zero crossings of successive positive to negative transitions, using linear interpolation. The results are shown below.
Canonical Calibration -- kVoltageTime
RG Calibration -- kVTFullRG*
JW Calibration -- kVTFullJW*
Conclusions
The JW calibration is clearly the superior one, reducing the RMS of the clock period distribution to 81 picoseconds. Just as a point of interest the event which produced the two anomalously low clock periods in the JW calibrationis shown below. Clearly this is a pathological event and the anaomalous values come from a miscalculation of the clock period rather than a poor timing calibration.
Copyright © 2006 Ryan Nichol, (last modified 07 Jun 2007)